Amazing Photo Captures 84 Million Stars in Our Milky Way Galaxy

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Astronomers have catalogued 84 million stars at the heart of the
Milky Way galaxy using an enormous cosmic photo snapped by a
telescope in Chile, a view that is billed as the largest survey
ever of the stars in our galaxy's core.

The
staggering 9-gigapixel picture was created with data
gathered by the Visible and Infrared Survey Telescope for
Astronomy (VISTA), an instrument at the European Southern
Observatory's Paranal Observatory in northern Chile. The zoomable
image is so large that it would measure 30 feet long by 23 feet
tall (9 by 7 meters) if printed with the resolution of a typical
book, researchers said.

The catalogue derived from the new image contains 10 times more
stars than previous studies have provided. It should help
astronomers better understand the structure and evolution of our
home galaxy,
researchers said.

"By observing in detail the myriads of stars surrounding the
center of the Milky Way we can learn a lot more about the
formation and evolution of not only our galaxy, but also spiral
galaxies in general," study lead author Roberto Saito, of the
Pontificia Universidad Católica de Chile, Universidad de
Valparaíso and The Milky Way Millennium Nucleus, said in a
statement. [ Stunning
Photos of Our Milky Way Galaxy ]

The huge new picture probes the
Milky Way 's central bulge, a concentration of ancient stars
found near the core of most spiral galaxies. Getting good looks
at this region is not an easy task.

"Observations of the bulge of the Milky Way are very hard because
it is obscured by dust," said co-author Dante Minniti, also of
Pontificia Universidad Catolica de Chile. "To peer into the heart
of the galaxy, we need to observe in infrared light, which is
less affected by the dust."

VISTA was able to do just that, snapping thousands of infrared
images that were combined to generate a monumental color mosaic
measuring 108,200 by 81,500 pixels. It's one of the biggest
astronomical images ever produced, researchers said.

Astronomers identified 173 million different objects in the
9-billion-pixel image, of which 84 million could be confirmed as
stars. The rest were distant objects such as galaxies, or they
were too faint or blended to be identified conclusively.

Saito and his team then plotted the brightness of each star
against its color, creating a color-magnitude diagram with 84
million data points. These diagrams are valuable tools, helping
astronomers study star properties such as temperature, mass and
age.

"Each star occupies a particular spot in this diagram at any
moment during its lifetime," Minniti said. "Where it falls
depends on how bright it is and how hot it is. Since the new data
gives us a snapshot of all the stars in one go, we can now make a
census of all the stars in this part of the Milky Way."

The astronomers are making their data publicly available, so
other research teams can use it to make exciting finds of their
own.

The team published their results in the August issue of the
journal Astronomy & Astrophysics.